Cupped elastic plunger type snubber



June 2, 1959 w. M. SHEETS Re- 24,654

` CUPPED ELASTICVPLUNGER TYPE SNUBBER 4original Filed March 15, 1952 Tf1/i Z Liam MShee'S 'peripheral rim of the latter.

United States Patent O "CUPPED ELASTIC PLUNGER TYPE SNUBBER William M. Sheets, Portland, Oreg.

Original No. 2,724,588, dated November 2'2, 1955, Serial No. 276,739, March 15, 1952. Application for reissue November 20, 1957, Serial No. 698,892

9 Claims. (Cl. 267-35) 'Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specilicatlon; matter printed in italics indicates the additions made by reissue.

My invention relates to a compression resistant spring device or snubber of the type used to reduce or absorb vibration in machinery, to slow and stop a moving part in a machine or gun or, in general, to serve any of the diverse uses to which a compression spring may be put. More particularlyy my invention replaces the conventional metallic compression spring with a stacked plurality of resilient and deformable hollow cups which are arranged to resist compression forces both by the flexing of the deformable cups and by the compression of air which is entrapped therein.

One object of my invention is to provide a spring device or snubber of the above type in which the resilient and deformable elements are non-metallic and, further, are not subject to rubbing or to frictional wear whereby the resistance to compression and, thereby, the snubbing action will remain substantially uniform throughout a long period of time and in spite of repeated severe usage.

In general, shock absorbers, vibration dampers and the like may be thought of as mere specialized forms of a spring. Thus, a spring is a deformable device that recovers its original shape when released after deformation and a shock absorber or a vibration dampener also is a deformable device that recovers its shape. Certain types of shock absorbers, however, are somewhat different from a spring in that deformation and recovery of the original shape proceed at different rates. That is to say, recovery of the original shape is slow or purposely is delayed in some shock absorbers. For example, the typical automobile shock absorber works in opposition to the suspension leaf spring by giving quite easily when the spring is flexed but by delaying or inhibiting the rebound or recovery thereof toward the original shape. It is for these reasons that I term my invention a spring device or snubber rather than a shock absorber, the recovery of the original shape thereof taking place substantially without opposition and substantially at the same rate as the deformation.

To this end, my invention includes a hollow body member having a smooth cylindrical bore in which a movable piston member is mounted. Within the bore, a stacked plurality of resilient and deformable cup members are spaced one from another by a similar plurality of stii circular disk members. Each circular disk member, in turn, is provided with a smooth plane face which terminates peripherally in an upstanding rim portion. The resilient cup members, on the other hand, each are provided with a conical hollow bore which is open to one end and which delines an air chamber. In assembling the spring device, each of the cup members is supported upon a corresponding one of the circular disks with the periphery of the conical bore air chamber resting ush against the plane face of the disk and closely bounded by the upstanding Thus, when the piston mem- Such a squeeze and ICC compression produces a dual resistance to compression or snubbing action in that the air entrapped within the hollow conical bore air chambers is compressed and the walls of the cup members are ilexed and deformed, all at the same time. Further, by virtue of the fact that the cup members are made smaller than the smooth cylindrical bore and are retained against excessive lateral movement by the upstanding rim on each disk member, the cup members themselves never are permitted to contact the walls of the cylindrical bore and no rubbing or frictional wear of the flexing parts of the spring device is possible.

In accord with the above summary description, it is a further object of my invention to provide a compound deformable spring device which is arranged to employ flexing of a resilient member and compression of entrapped air without employing kinetic friction or rubbing, all to the end of compressibly and deformably absorbing vibration or stopping movement without inhibiting immediate return of the spring device to the original shape when the vibration or movement ceases.

These and other objects and advantages of my invention will be set forth in the following detailed description, taken in conjunction with the accompanying drawing, wherein:

Fig. 1 is a side view, partially broken away and partially in section, showing my spring device or snubber in the extended and relaxed postion;

Fig. 2 is a similar view which is foreshortened and partially broken away in order to show the spring device of Fig. 1 in the deformed or compressed position and in order to indicate the dual vresistance of the entrapped air and the flexing of the walls of the resilient elements;

Fig. 3 is a detail view, also partially broken away, showing one of the resilient land deformable cup members together with the conical hollow bore thereof which is open to one end to deline an inner chamber; and

Fig. 4 is a detail View, partially in section, showing one of the circular disks and more particularly illustratng the smooth plane upper face thereof which terminates peripherally in an upstanding rim portion.

In the drawings, I have shown a preferred embodiment of my spring device wherein an elongated body member 5 is provided with a smooth cylindrical bore 6. One end of the cylindrical bore 6 is closed and a mounting element 7 is formed integral therewith. The vopposite end of the bore 6, on the other hand, is closed by means of a threaded cap member 8 having a cylindrical aperture 9 axially therein. This aperture 9, in turn, slidably accommodates a rod which terminates in a second mounting element 11. As shown in Fig. 1, the rod 10 is foreshortened, the actual length thereof being approximately two-thirds the length of the body member 5 in order that the mounting element 11 will, at all times, remain outside the bore 6.

Progressing to the interior of the body member 5, a piston member 12 is carried by the rod 10 and this piston member slidably is accommodated within the cylindrical bore 6 for rectilinear movement therein. Thus, when the spring device functions, the piston member 12 is -movable between the extended position of Fig. l, wherein it abuts the threaded cap 8, to the deformed or compressed position of Fig. 2, wherein it is spaced longitudinally from the cap.

Intermediate the piston member 12 and the closed end of the body member 5, a plurality of stacked compression resistant units are mounted. yIn accord with one object of my invention, each of these units provides a dual resistance to compression or to movement of the piston from the position of Fig. l to the position of Fig. 2 by utilizing both the compression of entrapped air and the resistance to exing of resilient deformable elements. Thus, each compression resistant unit includes a resilient cup member 13 which is formed of rubber or the like 3, and a stiff circular disk member 14 which is' formed of metal or of a tough plastic material. Further, each of the disk members.14. slidablyrisltted within lthe smooth cylindrical bore l6 Af or-l movement longitudinally thereof and, during such movement, the resilient cup members 13 are deformed and flexed. a I

In detail (see Fig. 3), each ofthe resilient cup members is provided with a conical body 15 and with an enlarged circular head 16 which extends laterally out from the apex of the conical body... Internally, the conical body of each resilient cup member bounds an open conical bore 17, the base of which'pis defined by a circular peripheral lip 18, an annular llangerportionlZl extending inwardly therefrom. Similarly, each of the circular disk members 14 (seeV Fig. 4)` carries a smooth plane upper face 19 which terminates peripherally in an upstanding rim portion 20. I n size, the peripheral lip H18 of each resilient cup member is made to lttightly and sealinglyy within the upstanding rim portion 20 on a corf responding one of the vdisk 1members I.14. Further, the base of the annular flangeV portion 21 restsV upon the plane face 19 so as to seal thereagainst when a compressive force is exerted upon the `cup member. rIn this manner, the conical bore 17 effectively is `sealed off Vanda'ir which is entrapped and compressed therein is prevented from escaping. ,y

In assembling kone of the spring devices of my invention, the threaded cap 8 is removed from the end of the body member and the various resilient cup members 13 and circular disk members 14 are stacked in correlated relationship as shown in Fig. 1. Thereafter, the rod 1t) and piston member 12 are assembled with the threaded cap 8 and this entire assembly is joined with the body member 5. Such an assembly makes evident several factors which contribute to the efficiency of the spring device. Firstly, the enlarged circular head 16 of the endmost resilient cup member 13 rests upon the end of the cylindrical bore k6 and the remaining circular heads each support one of the disk members 14. The end disk member 14, in turn, `rests upon the piston member 12 and the peripheral lip 18 on each cup member fits within the upstanding rim portion 20 on a corresponding one of the disk members. This latter disposition of elements is of critical importance to my invention. Thus, as previously mentioned, the upper face 19 of each circular diskis plane and smooth and the peripheral lip 18 and annular ange 21 on the adjoining cup member tit quite tightly thereagainst. For these reasons, the open conical bore 17 of each cup member is sealed in order to define an air chamber. That is to say, air which is entrapped within each of the conical bores 17 when the spring device is assembled will be compressed when the piston head 12 moves from the position in Fig. 1 to the position of Fig. 2. Initially, as a comparison of these two figures will indicate, the annular flange 21 is pressed down against the face 19. That is to say, as a compressive force first is exerted upon the cupl member, the walls begin to flex and bulge outwardly. However, since the rim 20 prevents lateral movement of the lip portion 18, the entirey wall of the cup acts like a bell crank or lever, the upper portion of theV wall moving laterally out and thus forcing the annular flange 21 downwardly. Further, the greater the compressive force, the tighter the cup member and the annular ange are pressedagainst the face 19. This is an important feature of my invention and the compression of air in each of the resilient cup, members 13 which thereby is assured and is sealed against escape is a rst element in the resistance to compression of the spring device.

The second element of resistance is illustrated in Fig. 2 ,wherein it is shown that the,wall. which bounds the conical body of each cup member llexes and bulgcs laterally out under compressive forces. y,In function, vthis bulging* is .-si1nilar.to,thatwhich takes place. `when. any rubber or similar resilient material is compressed.l However, inlaccord with another important feature of my invention, the `upstanding rim portion 20 on each disk member prevents the bulging cup member from coming into physical Contact withthe smooth cylindrical bore 6. That is to say, the opstanding rim portion 20 conlines the lateraly ilexure of the corresponding cup` member 13 so the latter cannot bulge laterally beyond the peripheral outline of the former. In this manner, I have eliminated substantially all rubbing contact and, if the friction between the disk members 14 and the cylindrical bore be ignored, I have eliminated all kinetic friction from my spring device. In further function, the elimination of friction assures a rather quick return to the original position when the load upon the device is removed.

In use, my spring device may serve diverse functions. For example, the mounting elements 7 yand`11 maybe secured intermediate a vibrating piece of machinery and the base or suspension therefor. In this case, .the normal. position of the various elements will beintermediate the position of Fig. l and Fig. 2 orwill be somewhat similar to the latter position. Thatk is to say, vibration of the machinery `will l,cause the variousresilierit ,cup members 13 to flex and toV bulge as the piston member 12 moves back and forth rectilinearly withinthe smooth cylindrical bore 6. When increased compressive forces are exerted upon the spring device, the piston member 12 will move inwardly and, when. these foces let up somewhat, the piston member will move back toward the position o f Fig. l. In effecting these various movements, it will be noted that my spring device resists compression and absorbs vibration with a dual function. Firstly, the resilient and deformable cup members 13 bulge laterally out and llex back and forth from the position of Fig. l to the position of Fig. 2. In so doing, however, the upstanding rim portions 20 prevent the periphery of the cup members from coming into actual rubbing contact with the smooth cylindrical bores 6. Secondly, air which is entrapped within the open conical bores 17 is compressed as the cup members deform since the peripheral lip on each cup is in sealing contact with the smooth plane upper face 19 of each disk member. There is thus provided a maximum resistance to compression yet a large overall movement of the piston 12 is accommodated without utilizing kinetic friction or rubbing contact of one part with` another.V In actual use, the spring device has been found to possess` many advantages in diverse industrial applications. Further, in contrast with a conventional metallic compression spring, the effective life of myr spring device is quite long and the resistance to compression thereof is uniform over that life span even with severe usage.

I claim: Y

l. A compound spring device, comprising a hollow body member having an elongated smooth cylindrical bore in which slidably is mounted a piston member, lsaid smooth bore slidably `accommodating a stacked plurality of resilient and deformable cup members spaced longitudinally one from another by a plurality of stiff circular disk members, each circular disk having an npstanding rimportion, each resilient cup member having a conical hollow bore open to one end thereof and defining an air chamber, a circular peripheral lip bounding the base of each said conical bore, each said peripheral lip being slidably retained within a corresponding one of said upstanding rim portions, said cup members being smaller in diameter than saidy smooth bore and being spaced therefrom Vin deformed as well as extended condition. u

2. A spring device, comprising a hollow body member having an elongated smooth cylindrical bore, a movable piston member mounted within said cylindrical bore, said smooth bore slidably accommodating a stacked plurality of resilient and deformable cup members which are.V spaced longitudinally one from anotherbya plurality of.. stili circular disk members, said cuppmembersvbeing deformed when `said piston is moved within said bore,

each circular disk having a smooth plane face which terminates peripherally on an upstanding rim portion, each resilient cup member having a conical body bounding an open conical bore to define an air chamber and further having an enlarged circular head which extends laterally out from the apex thereof, the hase of said conical bore being bounded by a circular peripheral lip which rests upon the smooth plane face of a corresponding one of said disks and slidably is retained within the rim upstanding therefrom, said cup members being smaller in diameter than said smooth bore and being spaced therefrom in deformed as well as extended condition, said piston member 4being arranged to bear against one of said disks and the enlarged circular head of one of said cup members being arranged to bear against the opposite end of said cylindrical bore so that movement of said piston will deform said cup members and compress the air trapped in the air chambers thereof.

3. A compression resistant spring device, comprising a resilient cup member formed of rubber or the like and having a conical body adapted for compression in a direction axially of the conical shape, a conical bore opening in from the base of said conical body and terminating adjacent the apex thereof, the base of said body and bore being delined and bounded by a circular peripheral lip, and a stiff circular disk member having a smooth plane face which terminates peripherally in an upstanding circular rim portion, said circular peripheral lip being rested sealingly upon said plane face and the outer periphery thereof being rested sealingly in abutment with the inner periphery of said circular rim portion, the outer periphery of said circular rim portion exceeding in dimension the greatest girth of said cup member in the axially compressed position of the cup member.

4. In a compound spring device having an elongated smooth cylindrical bore in which is stacked a plurality of two piece compression resistant units, the rst piece of each unit including a resilient conical cup member which is deformable in response to a compressive force exerted thereon in an axial direction, a conical bore opening in from the base of each conical cup member and defining an air entrapment chamber, the second piece of each unit including a circular disk member slidable longitudinally in said smooth cylindrical bore and having a plane face terminating peripherally in an upstanding rim, each said plane face sealingly abutting the Ibase of a corresponding one of said conical bore air chambers and each said rim confining the base of the same cup member against deformation laterally beyond the peripheral outline of the disk member.

5. A spring device, comprising a hollow body member having an elongated smooth cylindrical bore, a movable piston member mounted within said cylindrical bore, said smooth bore slidably accommodating a stacked plurality of resilient and deformable cup members which are spaced longitudinally one from another by a plurality of stiff circular disk members, said cup members being deformed when said piston is moved within said bore, each circular disk having a smooth plane face which terminates peripherally on an upstanding rim portion, each resilient cup member having a conical body lbounding an open conical bore to define an air chamber and further having an enlarged circular head which extends laterally out from the apex thereof, the base of said conical bore being bounded by a circular peripheral lip having an inner annular ange which rests upon the smooth plane face of a corresponding one of said disks and slidably is retained within the rim upstanding therefrom, said cup members being smaller in diameter than said smooth bore and being spaced therefrom in deformed as well as extended condition, said piston member being arranged to bear against one of said disks and the enlarged circular head of one of said cup members lbeing arranged to bear against the opposite end of said cylindrical bore so that movement of said piston will deform said cup members and compress the air trapped in the air chambers thereof.

6. A compound spring device comprising a tubular body member, a plurality of cup members resliently contractable longitudinally and slidably received in stacked relationship in saidV tubular body member, stil?t plate members engaged between and longitudinally separating said cup members from each other and closing their cup openings to define closed air chambers within said cup members, force-applying means in said tubular body member for exerting a longitudinal contracting force on said stacked cup members, and a band encircling and confining the open end of each cup member for limiting lateral expansion thereof during longitudinal contraction of said cup members by said force-applying means, said cup members being of suciently smaller width than the interior of said tubular body member that they are spaced from the inner wall of said tubular body member both in relaxed condition and in longitudinally contracted condition.

7. A compound spring device comprising a tubular body member, a plurality of cup members resiliently contractable longitudinally and slidably received in stacked relationship in said tubular body member, each cup member having an enlarged head extending laterally from the closed end thereof, force-applying means in said tubular body member for exerting a longitudinal contracting force on said stacked cup members, stit plate members between and longitudinally separating said cup members from each other, each plate member having one side engaged with the open end of a cup member to dene a closed air chamber within such cup member and having an upstanding rim encircling and confining such cup member open end for limiting lateral expansion thereof during longitudinal contraction of said cup member by said force-applying means and the opposite side of such plate member engaging the enlarged head of another cup member, said cup members being su'ciently smaller than said tubular body member that they are spaced from the inner wall of said tubular body member both in relaxed condition and in longitudinally contracted condition.

8. In a compound spring device comprising a tubular body member, and a plurality of two-piece compressionresistant units resiliently contractable longitudinally and received in stacked relationship in said tubular body member, the jrst piece of each such unit including a cup member resiliently contractable by a force acting thereon longitudinally of said tubular body member, the second piece of each unit including a plate member slidable longitudinally in said tubular body member with one side engaging and closing the open end of said cup member to define a Iclosed air chamber within said cup member and having an upstanding rim encircling and confining such open etnd of said cup member for limiting lateral expansion thereof beyond said plate member in all longitudinally contracted conditions of said cup member.

9. A compression resistant spring device comprising a resilient cup member formed of rubber or the like and resiliently contractable longitudinally, a stiff plate member extending across and closing the open end of said cup member, said cup member having a peripheral lip projecting inwardly from the rim thereof adjacent to said plate member, tapered inwardly to a feather edge and pressed into sealing engagement with said plate member by pressure of air within said cup member during longtudinal contraction of said cup member, and a band movable with the peripheral portion of said open end of said cup member as said cup member contracts longitudinally and closely embracing the periphery of the open end of said cup member for confining such open end to hold said peripheral lip against appreciable expanding `with said plate membe.

5Reierenuce Cite# thefil of v1thispatent 5 ,01j they original Apatent y ,STATES 1,869793 Y' Bailey Al1g.-2, .1932 `2,115,458 Gaye; .v Apr'.^\26,21938 10 2,486,741 Gabriel NOV. 1, 1949 8 vBrown Jan. 9,*1951 Van Dorn Pebl 6,'1951 F 0113161??` PATENTS Great-Britain of'1f905 "'Gre'at' Britain Nov v23,\1925 Italy lMar. 14, 1:5938 `Sweden Ju1y"18, 1940 `Ge1many May 6,1942 y Great Britain May 25, 11949 Italy Nov. 30, 1950 

